/*-
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)vis.c       8.1 (Berkeley) 7/19/93";
#endif /* LIBC_SCCS and not lint */

#include "config.h"

#include <sys/cdefs.h>

#include <sys/types.h>
#include <limits.h>
#include <ctype.h>
#include <stdio.h>
#include "vis.h"

#define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')

/*
 * vis - visually encode characters
 */
char *
vis(dst, c, flag, nextc)
        char *dst;
        int c, nextc;
        int flag;
{
        c = (unsigned char)c;

        if (flag & VIS_HTTPSTYLE) {
                /* Described in RFC 1808 */
                if (!(isalnum(c) /* alpha-numeric */
                    /* safe */
                    || c == '$' || c == '-' || c == '_' || c == '.' || c == '+'
                    /* extra */
                    || c == '!' || c == '*' || c == '\'' || c == '('
                    || c == ')' || c == ',')) {
                        *dst++ = '%';
                        snprintf(dst, 4, (c < 16 ? "0%X" : "%X"), c);
                        dst += 2;
                        goto done;
                }
        }

        if ((flag & VIS_GLOB) &&
            (c == '*' || c == '?' || c == '[' || c == '#'))
                ;
        else if (isgraph(c) ||
           ((flag & VIS_SP) == 0 && c == ' ') ||
           ((flag & VIS_TAB) == 0 && c == '\t') ||
           ((flag & VIS_NL) == 0 && c == '\n') ||
           ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
                *dst++ = c;
                if (c == '\\' && (flag & VIS_NOSLASH) == 0)
                        *dst++ = '\\';
                *dst = '\0';
                return (dst);
        }

        if (flag & VIS_CSTYLE) {
                switch(c) {
                case '\n':
                        *dst++ = '\\';
                        *dst++ = 'n';
                        goto done;
                case '\r':
                        *dst++ = '\\';
                        *dst++ = 'r';
                        goto done;
                case '\b':
                        *dst++ = '\\';
                        *dst++ = 'b';
                        goto done;
                case '\a':
                        *dst++ = '\\';
                        *dst++ = 'a';
                        goto done;
                case '\v':
                        *dst++ = '\\';
                        *dst++ = 'v';
                        goto done;
                case '\t':
                        *dst++ = '\\';
                        *dst++ = 't';
                        goto done;
                case '\f':
                        *dst++ = '\\';
                        *dst++ = 'f';
                        goto done;
                case ' ':
                        *dst++ = '\\';
                        *dst++ = 's';
                        goto done;
                case '\0':
                        *dst++ = '\\';
                        *dst++ = '0';
                        if (isoctal(nextc)) {
                                *dst++ = '0';
                                *dst++ = '0';
                        }
                        goto done;
                }
        }
        if (((c & 0177) == ' ') || isgraph(c) || (flag & VIS_OCTAL)) {
                *dst++ = '\\';
                *dst++ = ((u_char)c >> 6 & 07) + '0';
                *dst++ = ((u_char)c >> 3 & 07) + '0';
                *dst++ = ((u_char)c & 07) + '0';
                goto done;
        }
        if ((flag & VIS_NOSLASH) == 0)
                *dst++ = '\\';
        if (c & 0200) {
                c &= 0177;
                *dst++ = 'M';
        }
        if (iscntrl(c)) {
                *dst++ = '^';
                if (c == 0177)
                        *dst++ = '?';
                else
                        *dst++ = c + '@';
        } else {
                *dst++ = '-';
                *dst++ = c;
        }
done:
        *dst = '\0';
        return (dst);
}

/*
 * strvis, strvisx - visually encode characters from src into dst
 *
 *      Dst must be 4 times the size of src to account for possible
 *      expansion.  The length of dst, not including the trailing NUL,
 *      is returned.
 *
 *      Strvisx encodes exactly len bytes from src into dst.
 *      This is useful for encoding a block of data.
 */
int
strvis(dst, src, flag)
        char *dst;
        const char *src;
        int flag;
{
        char c;
        char *start;

        for (start = dst; (c = *src); )
                dst = vis(dst, c, flag, *++src);
        *dst = '\0';
        return (dst - start);
}

int
strvisx(dst, src, len, flag)
        char *dst;
        const char *src;
        size_t len;
        int flag;
{
        int c;
        char *start;

        for (start = dst; len > 1; len--) {
                c = *src;
                dst = vis(dst, c, flag, *++src);
        }
        if (len)
                dst = vis(dst, *src, flag, '\0');
        *dst = '\0';

        return (dst - start);
}
